The present invention relates to a patterning unit of a warp knitting machine and more particularly to a patterning unit which controls the position of a guide point provided on a holding member individually by means of a linear pulse motor and to control methods thereof.
Hitherto, patterning of a warp knitting machine has been carried out by lapping patterning reeds in which guide points are mounted in a direction of a row of needles of the patterning reed based on means for lapping the patterning reeds such as a chain drum and an electronic patterning unit. However, because only the same quantity of lapping can be obtained for all the guide points mounted on one patterning reed, the superiority of patterning effect caused by a number of patterning reeds is proportional to the number of patterning reeds.
In view of the prior art problem described above, the present applicant proposed a new patterning unit previously in Japanese Patent Application No. 06-200750 (PCT/JP95/00032). This patterning unit is arranged such that guide points are provided individually as part of moving elements in a fixed guide path which corresponds to the patterning reed so as to be movable individually within the guide path.
However, even though the above-mentioned patterning unit patterns through the control of the movement of the moving elements on which the guide points are provided by utilizing linear pulse motors, it has left room for improvement in the following points:
(1) When a number of holding members increases, it is necessary to deal with it by thinning the linear pulse motor further;
(2) It is necessary to solve the problem of short life of a bearing caused by a large attraction force generated between a stator and a moving element of the linear pulse motor;
(3) It is necessary to take measures for preventing erroneous operation due to step-out power failure and external noise in the positioning control;
(4) With the increase of numbers of the holding members and of moving elements, it is necessary to improve a wiring method for wiring connection cables to the moving elements to realize a range in which the moving elements can be moved freely. This is a problem in mounting to the warp knitting machine;
(5) With the increase of numbers of the holding members and moving elements, it is necessary to simplify the assembly and adjustment of the unit. This is a problem in mounting to the warp knitting machine;
(6) It is necessary to correct a pitch error which might be caused by the difference in working precision of pitches of poles of a stator assembled to the holding member, in working precision of pitches of knitting needles and in expansion coefficient of the holding members due to environmental temperature changes;
(7) In operation, because a plurality of layers of patterning reeds, i.e. the holding members, are disposed, it is necessary to simplify the replacement of the guide point and its alignment with a knitting needle of each moving element which is located behind another; and
(8) With the increase of the number of moving elements to be mounted, a control method is required which allows each moving element to be positioned at high-speed in synchronism with the rapid rotation of the warp knitting machine while maintaining the free movable range of each moving element and which can realize the above-mentioned points (3) through (7) at low cost.